The factory alternator lead goes to the fuse box, then to the bat +. After pulling out my 4 volume Tacoma Manual set and reading, it appears there is a 140 amp fuse (i have the 130 amp tow package) inside the fuse box.

Will I need to upgrade this fuse to accomodate a 250 amp alternator? I assume the alternator lead to fuse box must remain (I already changed it out to 0 gauge) as this is how the fusebox/truck receives power...correct?

There is alot of info on various sites regarding dual battery installs and alternator upgrades...but have found nothing regarding this topic anywhere.

It has been suggested that I run my upgraded 0 gauge from the fusebox to the battery isolator...then ALSO run a direct 0 gauge (fused) from the alternator direct to the isolator.

This may work, as the current would be divided between the 2 wires, but doesnt seem ideal really.

Can I bypass the fusebox all together and go straight from the alt to the isolator or is the fusebox required to receive power through that circuit?

Could really use some help from someone who has upgraded to a HO alternator...someone with practical experience.

Thanks again.

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I have that alt you are talking bout and an optima yellow. I like to run 0 gauge from the DC power alt to a Rockford fosgate 180 amp buss fuse and then straight to the optima battery. Disconnect the wire that goes from fuse box to alt completely altogether, leaving only battery to fuse box and then battery to 180 amp fuse holder to the altenator. Don't use the isolator they suck! Other than that the alt is machined with very sharp edges and cut the f@$@ out of my hands so wear gloves, and the new one is so big it might make you think it won't fit but it will. This won't just be a one hour project unless you don't mind sloppy wiring. Well worth every penny imho my trucks interior lights have never been so bright. There is no instruction manual though and the top alt bracket needs the pushed in sleeve to be pushed out till it can sit flush or install may make you think you need to machine down their heavy duty spacer but you won't have to. Good luck enjoy the huge amt of extra power.